The present invention relates to a terminal holding structure wherein a terminal fitting provided at the distal end of the electrical lead is accommodated in a terminal chamber in a connector housing.
FIG. 5 illustrates a related structure wherein a terminal fitting (female terminal) 3 is received and held in a terminal chamber 2 in a connector housing 1. The terminal chamber 2 has a lance 6 projecting from one inner wall 4. The lance 6 includes, as shown in FIG. 6A, a step portion 8 on the tip of the flexible arm portion 7. The step portion 8 is engaged in a bore 10 formed on the box portion 9 of the terminal fitting 3. Formed on one side of the terminal chamber 2 is a stopper wall 11 to prevent the terminal fitting 3 from passing through that side. The other side of the terminal chamber 2 is an opening for insertion for inserting the terminal fitting 3 into the terminal chamber 2. The lance 6 projects toward the stopper wall 11 and is prevented from being disconnected from the other side of the terminal chamber 2 by engaging the bore 10 formed on the terminal fitting 3 with the step portion 8.
The height of the terminal chamber 2 is selected such that the terminal fitting 3 can be inserted easily and that a clearance is created between the terminal fitting 3 and an inner wall 5 opposing to the inner wall 4 even when the terminal fitting 3 is pressed by the lance 6 toward the inner wall 5. Therefore, when a force is exerted on the terminal fitting 3 in the direction of disconnection by pulling the lead 12, the terminal fitting 3 moves to an extent (within the range of clearance play).
In such a terminal holding structure, in order to hold the terminal fitting 3 in the terminal chamber 2, the terminal fitting 3 is inserted from the side of opening for insertion of the terminal chamber 2, and when the terminal fitting 3 and the lance 6 comes in contact with each other, the terminal fitting 3 is further inserted toward the stopper wall 11. When the terminal fitting 3 is inserted toward the stopper wall 11, the lance 6 deforms, and when the bore 10 is located over the step portion 8 of the lance 6, the bore 10 is engaged with the step portion 8. At this time, the extent of engagement of the bore 10 with the step portion 8 is, as shown in FIG. 6A, a sufficient length of L1. In this situation, the terminal fitting 3 is held in connected state by means of the lance 6.
However, when the terminal fitting 3 is pulled by pulling the lead 12, the terminal fitting 3 moves in the terminal chamber 2 within the range of clearance play as described above, and consequently, the extent of engagement L2 of the bore 10 with the step portion 8 decreases, and thus the force exerted by the lance 6 to hold the terminal fitting 3 within the terminal chamber 2 decreases by the amount corresponding to the length L3. As a result, when the lead is pulled with a significant force, the lance 6 may be deformed, or in the worst case, may be damaged.
Accordingly, it is an object of the present invention to present a terminal holding structure wherein the extent of engagement of the bore with the lance does not decrease even when the terminal fitting is moved in the terminal chamber within the range of clearance play by pulling the lead, and thus the reduction in the holding force thereof can be prevented.
In order to achieve the above object, according to the present invention, there is provided a connector housing for accommodating a connector terminal therein, comprising:
a chamber for accommodating the connector terminal, the chamber provided with an opening from which the connector terminal is inserted;
an engagement member formed on a first inner wall of the chamber for engaging with a first portion of the connector terminal so as to prevent the connector terminal from moving toward the opening; and
a backlash stopper formed on a second inner wall of the chamber opposing to the first inner wall such that a clearance is created between the connector terminal when the first portion of the connector terminal is completely engaged with the engagement member, but a second portion of the connector terminal is brought into contact with the backlash stopper when the first portion of the connector terminal is almost disengaged from the engagement member.
Preferably, the backlash stopper is arranged closer to the opening than the engagement member.
In such a terminal holding structure, when a force is exerted onto the connector terminal in the direction of disconnection by pulling a lead connected to the connector terminal, if there is a clearance between the backlash stopper and the second portion of the connector terminal, the extent of engagement of the first portion of the connector housing and the engagement member is large enough, and thus the force to hold the connector terminal within the chamber is not reduced.
On the other hand, when the connector terminal moves within the chamber so as not to create a clearance between the backlash stopper and the second portion of the connector terminal, the second portion comes into contact with the backlash stopper to prevent a decrease in the extent of engagement of between the first portion thereof and the engagement member. As a result, even if the connector terminal is moved in the chamber within the range of clearance play, the extent of engagement between the first portion thereof and the engagement member can be kept large enough, ensuring that the connector terminal is held in the chamber.
Preferably, the backlash stopper includes a guide slope on which the second portion of the connector terminal is slid toward such a direction that the first portion of the connector terminal is completely engaged with the engagement member when the second portion of the connector terminal is brought into contact therewith.
In this terminal holding structure, when the connector terminal moves in the chamber so as not to create any clearance between the backlash stopper and the second portion of the connector terminal, the second portion comes in contact with the guide slope on the backlash stopper, and the movement of the connector terminal in the chamber toward the side of the insertion opening urges the connector terminal toward the first inner wall. This prevents a decrease in the extent of engagement between the first portion of the connector terminal and the engagement member, that is, the extent of engagement does not decrease. Consequently, the reduction in the force to hold the connector terminal within the chamber is prevented.